Chino Hills, CA Accessory Structures: Garage Conversions (2026)

Chino Hills processes ADU garage conversions under Chino Hills Municipal Code § 16.10.140, the city's implementation of state ADU law at Government Code § 65852.2. Section 16.10.140(P)(3) tells homeowners directly what happens to the driveway: when a garage, carport, or other covered parking structure is converted into an ADU, or demolished to make room for one, the city does not require replacement of those parking spaces. The trade-off is that the primary dwelling is then deemed legal, non-conforming under Chapter 16.34 Parking and Loading; any later addition to the primary house still has to meet Chapter 16.34's parking standards even though the conversion itself is exempt.

The exterior treatment is where the city keeps design control. Section 16.10.140(Q)(3) requires the garage door to be removed entirely and replaced with a wall containing a window or door, and that wall has to match the architectural style, roof pitch, trim, and exterior materials and colors of the home's front elevation, not just approximate them. The section also folds in the California Building Code's habitability requirements for converting a garage into livable space, covering ceiling height, ventilation, and fire separation from any remaining garage area on the lot.

Because this section implements state ADU law, the city cannot impose parking replacement, minimum lot size, or owner-occupancy conditions beyond what Government Code § 65852.2 allows; the design standards in (Q)(3) are the kind of objective standard state law still permits a city to apply. Applications go through the Community Development Department as a building permit, not a discretionary hearing, once the design standards are met.